/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.actionbarsherlock.app;

import android.content.Context;
import android.graphics.drawable.Drawable;
import android.support.v4.app.FragmentTransaction;
import android.util.AttributeSet;
import android.view.Gravity;
import android.view.View;
import android.view.ViewDebug;
import android.view.ViewGroup;
import android.view.ViewGroup.MarginLayoutParams;
import android.widget.SpinnerAdapter;

/**
 * A window feature at the top of the activity that may display the activity
 * title, navigation modes, and other interactive items.
 * <p>
 * Beginning with Android 3.0 (API level 11), the action bar appears at the top
 * of an activity's window when the activity uses the system's
 * {@link android.R.style#Theme_Holo Holo} theme (or one of its descendant
 * themes), which is the default. You may otherwise add the action bar by
 * calling {@link android.view.Window#requestFeature
 * requestFeature(FEATURE_ACTION_BAR)} or by declaring it in a custom theme with
 * the {@link android.R.styleable#Theme_windowActionBar windowActionBar}
 * property.
 * <p>
 * By default, the action bar shows the application icon on the left, followed
 * by the activity title. If your activity has an options menu, you can make
 * select items accessible directly from the action bar as "action items". You
 * can also modify various characteristics of the action bar or remove it
 * completely.
 * </p>
 * <p>
 * From your activity, you can retrieve an instance of {@link ActionBar} by
 * calling {@link android.app.Activity#getActionBar getActionBar()}.
 * </p>
 * <p>
 * In some cases, the action bar may be overlayed by another bar that enables
 * contextual actions, using an {@link android.view.ActionMode}. For example,
 * when the user selects one or more items in your activity, you can enable an
 * action mode that offers actions specific to the selected items, with a UI
 * that temporarily replaces the action bar. Although the UI may occupy the same
 * space, the {@link android.view.ActionMode} APIs are distinct and independent
 * from those for {@link ActionBar}. <div class="special reference">
 * <h3>Developer Guides</h3>
 * <p>
 * For information about how to use the action bar, including how to add action
 * items, navigation modes and more, read the <a href="{@docRoot}
 * guide/topics/ui/actionbar.html">Action Bar</a> developer guide.
 * </p>
 * </div>
 */
public abstract class ActionBar {
    /**
     * Standard navigation mode. Consists of either a logo or icon and title
     * text with an optional subtitle. Clicking any of these elements will
     * dispatch onOptionsItemSelected to the host Activity with a MenuItem with
     * item ID android.R.id.home.
     */
    public static final int NAVIGATION_MODE_STANDARD = android.app.ActionBar.NAVIGATION_MODE_STANDARD;

    /**
     * List navigation mode. Instead of static title text this mode presents a
     * list menu for navigation within the activity. e.g. this might be
     * presented to the user as a dropdown list.
     */
    public static final int NAVIGATION_MODE_LIST = android.app.ActionBar.NAVIGATION_MODE_LIST;

    /**
     * Tab navigation mode. Instead of static title text this mode presents a
     * series of tabs for navigation within the activity.
     */
    public static final int NAVIGATION_MODE_TABS = android.app.ActionBar.NAVIGATION_MODE_TABS;

    /**
     * Use logo instead of icon if available. This flag will cause appropriate
     * navigation modes to use a wider logo in place of the standard icon.
     * 
     * @see #setDisplayOptions(int)
     * @see #setDisplayOptions(int, int)
     */
    public static final int DISPLAY_USE_LOGO = android.app.ActionBar.DISPLAY_USE_LOGO;

    /**
     * Show 'home' elements in this action bar, leaving more space for other
     * navigation elements. This includes logo and icon.
     * 
     * @see #setDisplayOptions(int)
     * @see #setDisplayOptions(int, int)
     */
    public static final int DISPLAY_SHOW_HOME = android.app.ActionBar.DISPLAY_SHOW_HOME;

    /**
     * Display the 'home' element such that it appears as an 'up' affordance.
     * e.g. show an arrow to the left indicating the action that will be taken.
     * Set this flag if selecting the 'home' button in the action bar to return
     * up by a single level in your UI rather than back to the top level or
     * front page.
     * <p>
     * Setting this option will implicitly enable interaction with the home/up
     * button. See {@link #setHomeButtonEnabled(boolean)}.
     * 
     * @see #setDisplayOptions(int)
     * @see #setDisplayOptions(int, int)
     */
    public static final int DISPLAY_HOME_AS_UP = android.app.ActionBar.DISPLAY_HOME_AS_UP;

    /**
     * Show the activity title and subtitle, if present.
     * 
     * @see #setTitle(CharSequence)
     * @see #setTitle(int)
     * @see #setSubtitle(CharSequence)
     * @see #setSubtitle(int)
     * @see #setDisplayOptions(int)
     * @see #setDisplayOptions(int, int)
     */
    public static final int DISPLAY_SHOW_TITLE = android.app.ActionBar.DISPLAY_SHOW_TITLE;

    /**
     * Show the custom view if one has been set.
     * 
     * @see #setCustomView(View)
     * @see #setDisplayOptions(int)
     * @see #setDisplayOptions(int, int)
     */
    public static final int DISPLAY_SHOW_CUSTOM = android.app.ActionBar.DISPLAY_SHOW_CUSTOM;

    /**
     * Set the action bar into custom navigation mode, supplying a view for
     * custom navigation. Custom navigation views appear between the application
     * icon and any action buttons and may use any space available there. Common
     * use cases for custom navigation views might include an auto-suggesting
     * address bar for a browser or other navigation mechanisms that do not
     * translate well to provided navigation modes.
     * 
     * @param view Custom navigation view to place in the ActionBar.
     */
    public abstract void setCustomView(View view);

    /**
     * Set the action bar into custom navigation mode, supplying a view for
     * custom navigation.
     * <p>
     * Custom navigation views appear between the application icon and any
     * action buttons and may use any space available there. Common use cases
     * for custom navigation views might include an auto-suggesting address bar
     * for a browser or other navigation mechanisms that do not translate well
     * to provided navigation modes.
     * </p>
     * <p>
     * The display option {@link #DISPLAY_SHOW_CUSTOM} must be set for the
     * custom view to be displayed.
     * </p>
     * 
     * @param view Custom navigation view to place in the ActionBar.
     * @param layoutParams How this custom view should layout in the bar.
     * @see #setDisplayOptions(int, int)
     */
    public abstract void setCustomView(View view, LayoutParams layoutParams);

    /**
     * Set the action bar into custom navigation mode, supplying a view for
     * custom navigation.
     * <p>
     * Custom navigation views appear between the application icon and any
     * action buttons and may use any space available there. Common use cases
     * for custom navigation views might include an auto-suggesting address bar
     * for a browser or other navigation mechanisms that do not translate well
     * to provided navigation modes.
     * </p>
     * <p>
     * The display option {@link #DISPLAY_SHOW_CUSTOM} must be set for the
     * custom view to be displayed.
     * </p>
     * 
     * @param resId Resource ID of a layout to inflate into the ActionBar.
     * @see #setDisplayOptions(int, int)
     */
    public abstract void setCustomView(int resId);

    /**
     * Set the icon to display in the 'home' section of the action bar. The
     * action bar will use an icon specified by its style or the activity icon
     * by default. Whether the home section shows an icon or logo is controlled
     * by the display option {@link #DISPLAY_USE_LOGO}.
     * 
     * @param resId Resource ID of a drawable to show as an icon.
     * @see #setDisplayUseLogoEnabled(boolean)
     * @see #setDisplayShowHomeEnabled(boolean)
     */
    public abstract void setIcon(int resId);

    /**
     * Set the icon to display in the 'home' section of the action bar. The
     * action bar will use an icon specified by its style or the activity icon
     * by default. Whether the home section shows an icon or logo is controlled
     * by the display option {@link #DISPLAY_USE_LOGO}.
     * 
     * @param icon Drawable to show as an icon.
     * @see #setDisplayUseLogoEnabled(boolean)
     * @see #setDisplayShowHomeEnabled(boolean)
     */
    public abstract void setIcon(Drawable icon);

    /**
     * Set the logo to display in the 'home' section of the action bar. The
     * action bar will use a logo specified by its style or the activity logo by
     * default. Whether the home section shows an icon or logo is controlled by
     * the display option {@link #DISPLAY_USE_LOGO}.
     * 
     * @param resId Resource ID of a drawable to show as a logo.
     * @see #setDisplayUseLogoEnabled(boolean)
     * @see #setDisplayShowHomeEnabled(boolean)
     */
    public abstract void setLogo(int resId);

    /**
     * Set the logo to display in the 'home' section of the action bar. The
     * action bar will use a logo specified by its style or the activity logo by
     * default. Whether the home section shows an icon or logo is controlled by
     * the display option {@link #DISPLAY_USE_LOGO}.
     * 
     * @param logo Drawable to show as a logo.
     * @see #setDisplayUseLogoEnabled(boolean)
     * @see #setDisplayShowHomeEnabled(boolean)
     */
    public abstract void setLogo(Drawable logo);

    /**
     * Set the adapter and navigation callback for list navigation mode. The
     * supplied adapter will provide views for the expanded list as well as the
     * currently selected item. (These may be displayed differently.) The
     * supplied OnNavigationListener will alert the application when the user
     * changes the current list selection.
     * 
     * @param adapter An adapter that will provide views both to display the
     *            current navigation selection and populate views within the
     *            dropdown navigation menu.
     * @param callback An OnNavigationListener that will receive events when the
     *            user selects a navigation item.
     */
    public abstract void setListNavigationCallbacks(SpinnerAdapter adapter,
            OnNavigationListener callback);

    /**
     * Set the selected navigation item in list or tabbed navigation modes.
     * 
     * @param position Position of the item to select.
     */
    public abstract void setSelectedNavigationItem(int position);

    /**
     * Get the position of the selected navigation item in list or tabbed
     * navigation modes.
     * 
     * @return Position of the selected item.
     */
    public abstract int getSelectedNavigationIndex();

    /**
     * Get the number of navigation items present in the current navigation
     * mode.
     * 
     * @return Number of navigation items.
     */
    public abstract int getNavigationItemCount();

    /**
     * Set the action bar's title. This will only be displayed if
     * {@link #DISPLAY_SHOW_TITLE} is set.
     * 
     * @param title Title to set
     * @see #setTitle(int)
     * @see #setDisplayOptions(int, int)
     */
    public abstract void setTitle(CharSequence title);

    /**
     * Set the action bar's title. This will only be displayed if
     * {@link #DISPLAY_SHOW_TITLE} is set.
     * 
     * @param resId Resource ID of title string to set
     * @see #setTitle(CharSequence)
     * @see #setDisplayOptions(int, int)
     */
    public abstract void setTitle(int resId);

    /**
     * Set the action bar's subtitle. This will only be displayed if
     * {@link #DISPLAY_SHOW_TITLE} is set. Set to null to disable the subtitle
     * entirely.
     * 
     * @param subtitle Subtitle to set
     * @see #setSubtitle(int)
     * @see #setDisplayOptions(int, int)
     */
    public abstract void setSubtitle(CharSequence subtitle);

    /**
     * Set the action bar's subtitle. This will only be displayed if
     * {@link #DISPLAY_SHOW_TITLE} is set.
     * 
     * @param resId Resource ID of subtitle string to set
     * @see #setSubtitle(CharSequence)
     * @see #setDisplayOptions(int, int)
     */
    public abstract void setSubtitle(int resId);

    /**
     * Set display options. This changes all display option bits at once. To
     * change a limited subset of display options, see
     * {@link #setDisplayOptions(int, int)}.
     * 
     * @param options A combination of the bits defined by the DISPLAY_
     *            constants defined in ActionBar.
     */
    public abstract void setDisplayOptions(int options);

    /**
     * Set selected display options. Only the options specified by mask will be
     * changed. To change all display option bits at once, see
     * {@link #setDisplayOptions(int)}.
     * <p>
     * Example: setDisplayOptions(0, DISPLAY_SHOW_HOME) will disable the
     * {@link #DISPLAY_SHOW_HOME} option. setDisplayOptions(DISPLAY_SHOW_HOME,
     * DISPLAY_SHOW_HOME | DISPLAY_USE_LOGO) will enable
     * {@link #DISPLAY_SHOW_HOME} and disable {@link #DISPLAY_USE_LOGO}.
     * 
     * @param options A combination of the bits defined by the DISPLAY_
     *            constants defined in ActionBar.
     * @param mask A bit mask declaring which display options should be changed.
     */
    public abstract void setDisplayOptions(int options, int mask);

    /**
     * Set whether to display the activity logo rather than the activity icon. A
     * logo is often a wider, more detailed image.
     * <p>
     * To set several display options at once, see the setDisplayOptions
     * methods.
     * 
     * @param useLogo true to use the activity logo, false to use the activity
     *            icon.
     * @see #setDisplayOptions(int)
     * @see #setDisplayOptions(int, int)
     */
    public abstract void setDisplayUseLogoEnabled(boolean useLogo);

    /**
     * Set whether to include the application home affordance in the action bar.
     * Home is presented as either an activity icon or logo.
     * <p>
     * To set several display options at once, see the setDisplayOptions
     * methods.
     * 
     * @param showHome true to show home, false otherwise.
     * @see #setDisplayOptions(int)
     * @see #setDisplayOptions(int, int)
     */
    public abstract void setDisplayShowHomeEnabled(boolean showHome);

    /**
     * Set whether home should be displayed as an "up" affordance. Set this to
     * true if selecting "home" returns up by a single level in your UI rather
     * than back to the top level or front page.
     * <p>
     * To set several display options at once, see the setDisplayOptions
     * methods.
     * 
     * @param showHomeAsUp true to show the user that selecting home will return
     *            one level up rather than to the top level of the app.
     * @see #setDisplayOptions(int)
     * @see #setDisplayOptions(int, int)
     */
    public abstract void setDisplayHomeAsUpEnabled(boolean showHomeAsUp);

    /**
     * Set whether an activity title/subtitle should be displayed.
     * <p>
     * To set several display options at once, see the setDisplayOptions
     * methods.
     * 
     * @param showTitle true to display a title/subtitle if present.
     * @see #setDisplayOptions(int)
     * @see #setDisplayOptions(int, int)
     */
    public abstract void setDisplayShowTitleEnabled(boolean showTitle);

    /**
     * Set whether a custom view should be displayed, if set.
     * <p>
     * To set several display options at once, see the setDisplayOptions
     * methods.
     * 
     * @param showCustom true if the currently set custom view should be
     *            displayed, false otherwise.
     * @see #setDisplayOptions(int)
     * @see #setDisplayOptions(int, int)
     */
    public abstract void setDisplayShowCustomEnabled(boolean showCustom);

    /**
     * Set the ActionBar's background. This will be used for the primary action
     * bar.
     * 
     * @param d Background drawable
     * @see #setStackedBackgroundDrawable(Drawable)
     * @see #setSplitBackgroundDrawable(Drawable)
     */
    public abstract void setBackgroundDrawable(Drawable d);

    /**
     * Set the ActionBar's stacked background. This will appear in the second
     * row/stacked bar on some devices and configurations.
     * 
     * @param d Background drawable for the stacked row
     */
    public void setStackedBackgroundDrawable(Drawable d) {
    }

    /**
     * Set the ActionBar's split background. This will appear in the split
     * action bar containing menu-provided action buttons on some devices and
     * configurations.
     * <p>
     * You can enable split action bar with {@link android.R.attr#uiOptions}
     * 
     * @param d Background drawable for the split bar
     */
    public void setSplitBackgroundDrawable(Drawable d) {
    }

    /**
     * @return The current custom view.
     */
    public abstract View getCustomView();

    /**
     * Returns the current ActionBar title in standard mode. Returns null if
     * {@link #getNavigationMode()} would not return
     * {@link #NAVIGATION_MODE_STANDARD}.
     * 
     * @return The current ActionBar title or null.
     */
    public abstract CharSequence getTitle();

    /**
     * Returns the current ActionBar subtitle in standard mode. Returns null if
     * {@link #getNavigationMode()} would not return
     * {@link #NAVIGATION_MODE_STANDARD}.
     * 
     * @return The current ActionBar subtitle or null.
     */
    public abstract CharSequence getSubtitle();

    /**
     * Returns the current navigation mode. The result will be one of:
     * <ul>
     * <li>{@link #NAVIGATION_MODE_STANDARD}</li>
     * <li>{@link #NAVIGATION_MODE_LIST}</li>
     * <li>{@link #NAVIGATION_MODE_TABS}</li>
     * </ul>
     * 
     * @return The current navigation mode.
     */
    public abstract int getNavigationMode();

    /**
     * Set the current navigation mode.
     * 
     * @param mode The new mode to set.
     * @see #NAVIGATION_MODE_STANDARD
     * @see #NAVIGATION_MODE_LIST
     * @see #NAVIGATION_MODE_TABS
     */
    public abstract void setNavigationMode(int mode);

    /**
     * @return The current set of display options.
     */
    public abstract int getDisplayOptions();

    /**
     * Create and return a new {@link Tab}. This tab will not be included in the
     * action bar until it is added.
     * <p>
     * Very often tabs will be used to switch between {@link Fragment} objects.
     * Here is a typical implementation of such tabs:
     * </p>
     * {@sample development/samples/ApiDemos/src/com/example/android/apis/app/
     * FragmentTabs.java complete}
     * 
     * @return A new Tab
     * @see #addTab(Tab)
     */
    public abstract Tab newTab();

    /**
     * Add a tab for use in tabbed navigation mode. The tab will be added at the
     * end of the list. If this is the first tab to be added it will become the
     * selected tab.
     * 
     * @param tab Tab to add
     */
    public abstract void addTab(Tab tab);

    /**
     * Add a tab for use in tabbed navigation mode. The tab will be added at the
     * end of the list.
     * 
     * @param tab Tab to add
     * @param setSelected True if the added tab should become the selected tab.
     */
    public abstract void addTab(Tab tab, boolean setSelected);

    /**
     * Add a tab for use in tabbed navigation mode. The tab will be inserted at
     * <code>position</code>. If this is the first tab to be added it will
     * become the selected tab.
     * 
     * @param tab The tab to add
     * @param position The new position of the tab
     */
    public abstract void addTab(Tab tab, int position);

    /**
     * Add a tab for use in tabbed navigation mode. The tab will be insterted at
     * <code>position</code>.
     * 
     * @param tab The tab to add
     * @param position The new position of the tab
     * @param setSelected True if the added tab should become the selected tab.
     */
    public abstract void addTab(Tab tab, int position, boolean setSelected);

    /**
     * Remove a tab from the action bar. If the removed tab was selected it will
     * be deselected and another tab will be selected if present.
     * 
     * @param tab The tab to remove
     */
    public abstract void removeTab(Tab tab);

    /**
     * Remove a tab from the action bar. If the removed tab was selected it will
     * be deselected and another tab will be selected if present.
     * 
     * @param position Position of the tab to remove
     */
    public abstract void removeTabAt(int position);

    /**
     * Remove all tabs from the action bar and deselect the current tab.
     */
    public abstract void removeAllTabs();

    /**
     * Select the specified tab. If it is not a child of this action bar it will
     * be added.
     * <p>
     * Note: If you want to select by index, use
     * {@link #setSelectedNavigationItem(int)}.
     * </p>
     * 
     * @param tab Tab to select
     */
    public abstract void selectTab(Tab tab);

    /**
     * Returns the currently selected tab if in tabbed navigation mode and there
     * is at least one tab present.
     * 
     * @return The currently selected tab or null
     */
    public abstract Tab getSelectedTab();

    /**
     * Returns the tab at the specified index.
     * 
     * @param index Index value in the range 0-get
     * @return
     */
    public abstract Tab getTabAt(int index);

    /**
     * Returns the number of tabs currently registered with the action bar.
     * 
     * @return Tab count
     */
    public abstract int getTabCount();

    /**
     * Retrieve the current height of the ActionBar.
     * 
     * @return The ActionBar's height
     */
    public abstract int getHeight();

    /**
     * Show the ActionBar if it is not currently showing. If the window hosting
     * the ActionBar does not have the feature
     * {@link Window#FEATURE_ACTION_BAR_OVERLAY} it will resize application
     * content to fit the new space available.
     */
    public abstract void show();

    /**
     * Hide the ActionBar if it is currently showing. If the window hosting the
     * ActionBar does not have the feature
     * {@link Window#FEATURE_ACTION_BAR_OVERLAY} it will resize application
     * content to fit the new space available.
     */
    public abstract void hide();

    /**
     * @return <code>true</code> if the ActionBar is showing, <code>false</code>
     *         otherwise.
     */
    public abstract boolean isShowing();

    /**
     * Add a listener that will respond to menu visibility change events.
     * 
     * @param listener The new listener to add
     */
    public abstract void addOnMenuVisibilityListener(OnMenuVisibilityListener listener);

    /**
     * Remove a menu visibility listener. This listener will no longer receive
     * menu visibility change events.
     * 
     * @param listener A listener to remove that was previously added
     */
    public abstract void removeOnMenuVisibilityListener(OnMenuVisibilityListener listener);

    /**
     * Enable or disable the "home" button in the corner of the action bar.
     * (Note that this is the application home/up affordance on the action bar,
     * not the systemwide home button.)
     * <p>
     * This defaults to true for packages targeting &lt; API 14. For packages
     * targeting API 14 or greater, the application should call this method to
     * enable interaction with the home/up affordance.
     * <p>
     * Setting the {@link #DISPLAY_HOME_AS_UP} display option will automatically
     * enable the home button.
     * 
     * @param enabled true to enable the home button, false to disable the home
     *            button.
     */
    public void setHomeButtonEnabled(boolean enabled) {
    }

    /**
     * Returns a {@link Context} with an appropriate theme for creating views
     * that will appear in the action bar. If you are inflating or instantiating
     * custom views that will appear in an action bar, you should use the
     * Context returned by this method. (This includes adapters used for list
     * navigation mode.) This will ensure that views contrast properly against
     * the action bar.
     * 
     * @return A themed Context for creating views
     */
    public Context getThemedContext() {
        return null;
    }

    /**
     * Listener interface for ActionBar navigation events.
     */
    public interface OnNavigationListener {
        /**
         * This method is called whenever a navigation item in your action bar
         * is selected.
         * 
         * @param itemPosition Position of the item clicked.
         * @param itemId ID of the item clicked.
         * @return True if the event was handled, false otherwise.
         */
        public boolean onNavigationItemSelected(int itemPosition, long itemId);
    }

    /**
     * Listener for receiving events when action bar menus are shown or hidden.
     */
    public interface OnMenuVisibilityListener {
        /**
         * Called when an action bar menu is shown or hidden. Applications may
         * want to use this to tune auto-hiding behavior for the action bar or
         * pause/resume video playback, gameplay, or other activity within the
         * main content area.
         * 
         * @param isVisible True if an action bar menu is now visible, false if
         *            no action bar menus are visible.
         */
        public void onMenuVisibilityChanged(boolean isVisible);
    }

    /**
     * A tab in the action bar.
     * <p>
     * Tabs manage the hiding and showing of {@link Fragment}s.
     */
    public static abstract class Tab {
        /**
         * An invalid position for a tab.
         * 
         * @see #getPosition()
         */
        public static final int INVALID_POSITION = -1;

        /**
         * Return the current position of this tab in the action bar.
         * 
         * @return Current position, or {@link #INVALID_POSITION} if this tab is
         *         not currently in the action bar.
         */
        public abstract int getPosition();

        /**
         * Return the icon associated with this tab.
         * 
         * @return The tab's icon
         */
        public abstract Drawable getIcon();

        /**
         * Return the text of this tab.
         * 
         * @return The tab's text
         */
        public abstract CharSequence getText();

        /**
         * Set the icon displayed on this tab.
         * 
         * @param icon The drawable to use as an icon
         * @return The current instance for call chaining
         */
        public abstract Tab setIcon(Drawable icon);

        /**
         * Set the icon displayed on this tab.
         * 
         * @param resId Resource ID referring to the drawable to use as an icon
         * @return The current instance for call chaining
         */
        public abstract Tab setIcon(int resId);

        /**
         * Set the text displayed on this tab. Text may be truncated if there is
         * not room to display the entire string.
         * 
         * @param text The text to display
         * @return The current instance for call chaining
         */
        public abstract Tab setText(CharSequence text);

        /**
         * Set the text displayed on this tab. Text may be truncated if there is
         * not room to display the entire string.
         * 
         * @param resId A resource ID referring to the text that should be
         *            displayed
         * @return The current instance for call chaining
         */
        public abstract Tab setText(int resId);

        /**
         * Set a custom view to be used for this tab. This overrides values set
         * by {@link #setText(CharSequence)} and {@link #setIcon(Drawable)}.
         * 
         * @param view Custom view to be used as a tab.
         * @return The current instance for call chaining
         */
        public abstract Tab setCustomView(View view);

        /**
         * Set a custom view to be used for this tab. This overrides values set
         * by {@link #setText(CharSequence)} and {@link #setIcon(Drawable)}.
         * 
         * @param layoutResId A layout resource to inflate and use as a custom
         *            tab view
         * @return The current instance for call chaining
         */
        public abstract Tab setCustomView(int layoutResId);

        /**
         * Retrieve a previously set custom view for this tab.
         * 
         * @return The custom view set by {@link #setCustomView(View)}.
         */
        public abstract View getCustomView();

        /**
         * Give this Tab an arbitrary object to hold for later use.
         * 
         * @param obj Object to store
         * @return The current instance for call chaining
         */
        public abstract Tab setTag(Object obj);

        /**
         * @return This Tab's tag object.
         */
        public abstract Object getTag();

        /**
         * Set the {@link TabListener} that will handle switching to and from
         * this tab. All tabs must have a TabListener set before being added to
         * the ActionBar.
         * 
         * @param listener Listener to handle tab selection events
         * @return The current instance for call chaining
         */
        public abstract Tab setTabListener(TabListener listener);

        /**
         * Select this tab. Only valid if the tab has been added to the action
         * bar.
         */
        public abstract void select();

        /**
         * Set a description of this tab's content for use in accessibility
         * support. If no content description is provided the title will be
         * used.
         * 
         * @param resId A resource ID referring to the description text
         * @return The current instance for call chaining
         * @see #setContentDescription(CharSequence)
         * @see #getContentDescription()
         */
        public abstract Tab setContentDescription(int resId);

        /**
         * Set a description of this tab's content for use in accessibility
         * support. If no content description is provided the title will be
         * used.
         * 
         * @param contentDesc Description of this tab's content
         * @return The current instance for call chaining
         * @see #setContentDescription(int)
         * @see #getContentDescription()
         */
        public abstract Tab setContentDescription(CharSequence contentDesc);

        /**
         * Gets a brief description of this tab's content for use in
         * accessibility support.
         * 
         * @return Description of this tab's content
         * @see #setContentDescription(CharSequence)
         * @see #setContentDescription(int)
         */
        public abstract CharSequence getContentDescription();
    }

    /**
     * Callback interface invoked when a tab is focused, unfocused, added, or
     * removed.
     */
    public interface TabListener {
        /**
         * Called when a tab enters the selected state.
         * 
         * @param tab The tab that was selected
         * @param ft A {@link FragmentTransaction} for queuing fragment
         *            operations to execute during a tab switch. The previous
         *            tab's unselect and this tab's select will be executed in a
         *            single transaction. This FragmentTransaction does not
         *            support being added to the back stack.
         */
        public void onTabSelected(Tab tab, FragmentTransaction ft);

        /**
         * Called when a tab exits the selected state.
         * 
         * @param tab The tab that was unselected
         * @param ft A {@link FragmentTransaction} for queuing fragment
         *            operations to execute during a tab switch. This tab's
         *            unselect and the newly selected tab's select will be
         *            executed in a single transaction. This FragmentTransaction
         *            does not support being added to the back stack.
         */
        public void onTabUnselected(Tab tab, FragmentTransaction ft);

        /**
         * Called when a tab that is already selected is chosen again by the
         * user. Some applications may use this action to return to the top
         * level of a category.
         * 
         * @param tab The tab that was reselected.
         * @param ft A {@link FragmentTransaction} for queuing fragment
         *            operations to execute once this method returns. This
         *            FragmentTransaction does not support being added to the
         *            back stack.
         */
        public void onTabReselected(Tab tab, FragmentTransaction ft);
    }

    /**
     * Per-child layout information associated with action bar custom views.
     * 
     * @attr ref android.R.styleable#ActionBar_LayoutParams_layout_gravity
     */
    public static class LayoutParams extends MarginLayoutParams {
        /**
         * Gravity for the view associated with these LayoutParams.
         * 
         * @see android.view.Gravity
         */
        @ViewDebug.ExportedProperty(mapping = {
                @ViewDebug.IntToString(from = -1, to = "NONE"),
                @ViewDebug.IntToString(from = Gravity.NO_GRAVITY, to = "NONE"),
                @ViewDebug.IntToString(from = Gravity.TOP, to = "TOP"),
                @ViewDebug.IntToString(from = Gravity.BOTTOM, to = "BOTTOM"),
                @ViewDebug.IntToString(from = Gravity.LEFT, to = "LEFT"),
                @ViewDebug.IntToString(from = Gravity.RIGHT, to = "RIGHT"),
                @ViewDebug.IntToString(from = Gravity.CENTER_VERTICAL, to = "CENTER_VERTICAL"),
                @ViewDebug.IntToString(from = Gravity.FILL_VERTICAL, to = "FILL_VERTICAL"),
                @ViewDebug.IntToString(from = Gravity.CENTER_HORIZONTAL, to = "CENTER_HORIZONTAL"),
                @ViewDebug.IntToString(from = Gravity.FILL_HORIZONTAL, to = "FILL_HORIZONTAL"),
                @ViewDebug.IntToString(from = Gravity.CENTER, to = "CENTER"),
                @ViewDebug.IntToString(from = Gravity.FILL, to = "FILL")
        })
        public int gravity = -1;

        public LayoutParams(Context c, AttributeSet attrs) {
            super(c, attrs);
        }

        public LayoutParams(int width, int height) {
            super(width, height);
            this.gravity = Gravity.CENTER_VERTICAL | Gravity.LEFT;
        }

        public LayoutParams(int width, int height, int gravity) {
            super(width, height);
            this.gravity = gravity;
        }

        public LayoutParams(int gravity) {
            this(WRAP_CONTENT, FILL_PARENT, gravity);
        }

        public LayoutParams(LayoutParams source) {
            super(source);

            this.gravity = source.gravity;
        }

        public LayoutParams(ViewGroup.LayoutParams source) {
            super(source);
        }
    }
}
